Method of dehydrating



Sept. 5, 1944. A. A. RoBBlNs METHOD oF DEHYDRATING Filed Feb. 16. 1943 L M W E m Cu SIDE W4 ADHESIVE BOTTOM haven-tar fbezjz" :.Q'. 'Robbins Patented Sept...f5, l1944 UNITED STATES 'PATE'.N'I# oFFlcE Albert A. Robbins, Pomona, Calif. ApplicationFebrnary 16, 1943, Serial No. 476,111

14 anims. (Cl. 21B- 8.5)

My invention relates to methods of dehydrating various substances and has particular reference to the dehydrating of oils and other'substances, the water content of which is required yto be lowered or to be maintained at a-lower than normal level.

In thepreparation of various kinds of oils for the market a considerable problem is presented y in the removal of water from such oils and elabas lubricating oils, such as petroleum oils adaptv ed for use in internal combustion engines and the like, should be water free.

It is therei'orean object of my invention to provide an extremely simple method by which the water content in oils may be removed.

It is another object of my invention to provide a methody by which the water content may be removed from oils during a period of storage of the oils and without requiring the employment of special apparatus or special process steps for so doing. It is another object of my invention to provide a storage vcontainer into which -oils containing water may be placed and in which the container is so constructed as to remove the moisture content Irom the oils and pass it through the walls of the container to the atmosphere but will prevent the ingress of moisture from the atmosphere.

Another object of my invention is to provide a method by which any article which has been treated to reduce its moisture'content below normal may be stored with assurance that the article will be maintained with its moisture content at least as low as at the time it was stored.

' Other objects and advantages of my invention will be apparent from a study of the following specifications, read in connection with the accompanying drawing, wherein Fig. 1 is a sectional view o! a portion of the wall of a container which may be employed in the practice of my invention;

Fig. 2 is a sectional view oi' a portion of a modied container wall whichmay he employed in the practice of a modified form of my invention; and

Fig. 3 is a diagrammatic view illustrating a still further modified view of my invention.

In the preparation of oils, particularly lubriwhich the oils were placed in suitable containers for storage and distribution. It has recently become common practice in the storage4 and distribution o! such oils to package such oils in hermeticallysealed metal cans or containers, the seal of which is broken only at the time the oil is to be put into an engine or otherwise immediately used as a lubricant. A further development of this manner of packaging oils has been the introduction into this industry of iiber containers as a substitute for the metal containers, again such containers beinghermetically sealed ai'.v the time they are lled and remain sealed until the oil is to be immediately used. Such liber containers may be of paper, cardboard or similar materials which are relatively porous to the passage of either oil or water and are required to be treated with suitable moisture and grease-proofing materials in order to render them serviceable as oil containers. i

One4 form of such container comprises a cylindrical drum, the walls of which are built up to n hermetically sealed to the cylindrical walls of the character have their interiors completely coated scopic salt such as magnesium chloride,

cating oils, for the market it has heretofore been with .a relatively simple grease-prooiing coating which is hygroscopic in character, oils which are' stored in such containers will, over a relatively short period of time, lose all oi' the moisture content which may be in the oil at the time it was placed in such containers. v

For example\a container may be used having fibrous walls such as indicated at I in Fig. 1, having a coating 2 o nits interior 'formed from a glue-glycerin-water mixture, in which thel glycerin to 'glue ratio is from approximately 10% to 200%, and to which has been added some hygronitrate, ammonium nitrate, sodium iodide or any other hygroscopic salt which will not react with hydrocarbons. Such containerwhen filled with oil and sealed will provide, by reason oi the glueglycerin interior coating, an oil-proof container which will prevent `the oil from escaping. However, any moisture which may be contained within the oil will contact the interior surface of the hygroscopic coating 2 and due to the fact that the moisture in the oil has a relatively high vapor pressure as compared to the lower vapor prescombined phenomena of interfacial surface tension between the hygroscopic oil-proof film and the moisture containing oil resting in contact with the hygroscopic film, the moisture will be absorbed by the hygroscopic. lm and will be given off to the porous walls of the container. The container, being exposed to the atmosphere, such moisture in the porous container walls will pass to the atmosphere at any time that the moisture content of the atmosphere becomes less than the moisture content in the container walls.

Thus even under climatic conditions of relatively high humidity, appreciable quantities of moisture leaving the oil and passing into the walls oi' the container will be extracted from the container walls until a balance is reached between the amount of moisture in` the container walls and the amount of moisture in the surrounding atmosphere. Each time the humidity of the surrounding atmosphere diminishes, additionalmoisture will be removed from the porous container walls as long as there is any moisture contained in the oil packaged in the container.

' A peculiar phenomenon is that the reverse action does not occur, namely, moisture from relatively humid air may pass into the porous walls of the container but will not pass inwardly through the hygroscopic grease-proofing film since there does not exist on the exterior of the film (that surface of the film adjacent the container walls) the difference in inter-facial surface tension and that difference in vapor pressure as exists on the face of the grease-proofing film which is contacted by the oil.

In actual practice oils containing a relatively high moisture content, such as crankcase drainings, have been stored in containers of the character described herein and immediately after the container is filled and sealed the porous walls of vthe container become so saturated with moisture removed from the oil as to become relatively flaccid. Upon further standing this moisture has passed to the surrounding atmosphere and the walls of the container become stiff. Upon opening the containers after a relatively short period of storage `of several days, the oil within the container is found to be moisture-free.

In other instances new oil which has been treated to reduce its moisture content to what has been considered a minimum has been found to give up additional moisture upon being packaged in a container as described herein and when the container is opened after a short period of storage the contents are found to be moisturefree.

IThus by storing oils in containers of the character described there appears to be a repeating process of removal of the moisture and its passage to the atmosphere each time the humidity of the surrounding atmosphere becomes less than the moisture content of the container walls, the procl.until all of the moisturev has been removed or ess consisting cfa uni-directional extraction of I moisture from the contents and its passage to the atmosphere while moisture from the atmosphere is effectively prevented from passing into the contents.

A modification of the procedure may be successfully employed in the packaging of different dehydrated fruits, vegetables or lother food products, in which the container walls la are treated with a. hygroscopic grease-proof film 2a of the character hereinbefore described upon the interior of the container while the exterior 0I tht until the porous wall la of the container has absorbed moisture to its saturation point'. No

i moisture being permitted to enter the container by reason of the moisture-proof external coating 3, such food products will be maintained with their moisture content lower than when they were placed in the container.

As a further modification, such dehydrated food products may be placed in a container such as illustrated in Fig. 3, in which Ithe porous walls of the container have been treated either internally or externally or both with a moistureproofing film and then a disk or other shaped piece of porous material 4 which has been coated with a hygroscopic grease-proofing film of the character described herein is inserted into the container prior to its seal. Such insert will then act to extract moisture from the contents to the limit of the absorptive power of the Porous material, thus maintaining the contents at a lower moisture content than at the time such contents were placed in the container.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined, in the appended claims.

I claim:

1. The method of dehydrating materials which comprises storing said material in a closed container, at least a portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a hydrosopic grease-proofing film. l

2. The method of dehydrating materials which comprises storing said material in a closed container, at least a portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a hygroscopic grease-proofing film, and exposing the exterior of Said portion to the atmosphere.

3. The method of dehydrating materials which comprises storing said material in a closed container, at least a portion of which is constructed of porous material capable of absorbing moisture from the material and releasing it to the atmosphere and lined on the interior surface with a hygroscopic grease-proofing film, and exposing the exterior of said portion to the atmosphere.

4. The method of dehvdrating materials which comprises storing said material in a closed container, at least a portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a film of glue and glycerin to which is added a hygroscopic salt.

5. The method of dehydrating materials which comprises storing said material ina closed container, at least a portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a film comprising glue and glycerin in glycerin to glue ratio of from 10% to 200%, to which has been added a hygroscopic salt.

6. The method of dehydrating materials which comprises storing said material in a closed container, at least a'portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a lm comprising glue and glycerin in glycerin to glue ratio of from 10% to 200%, to which has been added a hygroscopic salt which Will not chemically react with the material to be dehydrated.

7. 'I'he method of dehydrating oil which comprises storing said oil in a closed container, at least a portion of which is constructed of material capable of absorbing moisture and lined on the interior surface with a hygroscopic grease-proofing lm. y

8. The method of dehydrating materials which comprises storing said material in a closed contain'er, the exterior surface of which is impervious to moisture, at least a portion of said container interiorly of said surface being formed of material ture and the interior Wall of said container being formed of a moisture absorbent material coated with a lm of hygroscopic grease-proofing material.

11. The method of dehydrating oil which consists in storing said oil in a closed container, the wall of said container being formed of a moisture absorbentmaterial coated -on the interior surface with a lm of hygroscopic grease-proofing material. l

12. The method of dehydrating oil which con-4 sists in storing said oil in a closed container, the exterior surface of which is impervious to moisture and the interior wall of said container being formed of a moisture absorbent material coated with a lm of flexible hygroscopic grease-proofing material. 4

13. The method of dehydrating oil which consists in storing said oil in a closed container. the

wall of said container being formed of a moisture absorbent material coated on the interior surface with a film of liiexible hygroscopic grease-proofing material.

14. The method of dehydrating mineral .oils which consists in storing said oils in a closed container formed of a material capable of absorbing moisture and lined on the interior witha film comprising glue and glycerin in the glycerin to glue ratio of from 10% to 200% to which has been added a hygroscopic material of the group including glycerin, magnesium chloride, sodium nitrate, ammonium nitrate and sodiumiodide.

ALBERT A. RoBBINs. 

